Purpose We aimed to explore the risk factors of preoperative sleep quality in patients with lumbar spinal stenosis (LSS) and the association of sleep-related beliefs with sleep quality in these patients. Methods Sleep quality and related risk factors of sleep quality disturbances in patients with LSS preoperatively were assessed by questionnaires. Pittsburgh Sleep Quality Index (PSQI) for sleep quality, Oswestry Disability Index (ODI) for clinical outcomes, Visual Analog Scale for Pain (VAS Pain), Self-Rating Anxiety Scale (SAS) for anxiety level, and Dysfunctional Beliefs and Attitudes about Sleep (DBAS-16) for sleep-related beliefs were assessed. Bivariate logistic regression analysis was used to assess the risk factors of sleep quality disturbances. Results A total of 227 patients were enrolled, mean age 64 years (SD 13.1), 119 women (52%). The incidence of sleep quality disturbances in patients was 37% (83/227). Increased DBAS-16 scores (OR = 0.781; 95% CI, 0.725-0.841; p < 0.001) significantly decreased the probability of developing sleep quality disturbances, while increased anxiety levels (OR = 1.241; 95% CI, 1.152-1.337; p < 0.001) significantly increased the probability of developing sleep quality disturbances in patients. Factors including educational level, increased age, sex, preoperative length of stay, VAS Pain scores, and ODI scores showed no significant association and were therefore excluded from the model. Conclusions High levels of anxiety and mistaken sleep-related beliefs were risk factors of sleep quality disturbances in patients with LSS before surgery. The more mistaken sleep-related beliefs were, the greater the probability of sleep disturbances.